Network-selecting circuits



C. s. D'EMARES-T.

NETWORK SELECTING CIRCUITS.

APPLICATION FILED JAN. 4, I919.

' 1,377,242. Patented May 10,1921.

3 SHEEIS-SHEET l.

EZIE] J /IJH -II I male 61% 4 T [N V EN TOR. CAJZemamsZ B Y A TTORNE? Patented May 10, 1921.

3 SHEEES-SHEET 8.

C. S. DE-MAREST. NETWORK SELECTING CIRCUITS.

APPLlCATlON FILED 1AN.4, 1919. 1,377,242.

M mw n umrno STATES PA'IEN'F OFFICE.

CHARLES S. DEMAREST, OF BROOKLYN, NEW YORK, ASSIGNOR TO AMERICAN TELE- PHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

NETWORK-SELECTING CIRCUITS.

Specification of Letters Patent.

Patented May 10, 1921.

Application filed January 4, 1919. Serial No. 269,640.

To all whom it may concern:

Be it known that 1, CHARLES S. DEMAREST,

' cation.

This invention relates to repeater circuit and more particularly to repeater circuits equipped for the automatic selection of networks for balancing the lines with which the repeater may be associated.

n accordance with this invention, each end of a cord circuit repeater is provided wlth as many networks as may be necessary to balance the various types of transmission lines with which the repeater may be associated, and in addition several networks are provided for balancing various types of auxiliary apparatus, such as composite sets, which may be associated with some or all of the lines. Selecting relays are also provided, one for each network, the circuits of these relays being under the joint control of the line with which the repeater is associated and a series of controlling relays individual to the repeater. The repeater is also equipped with selectin circuits so arranged that when the two en s of the repeater are associated with transmission lines and the repeater controlling key actuated, all of the controlling relaysassociated with one end of the repeater are actuated to prepare the circuits ofall of the selecting relays associated with that end of the repeater. A relay associated with the line at the same time completes the circuit for such selecting relays as are necessary to select the various networks for balancing the line and its associated auxiliary apparatus. Upon the energization of the proper selecting relays the corresponding networks are connected to one end of the repeater and the controlling relays are restored to normal and their circuits held open so that false operation of any other selecting relays is prevented. As soon as the networks have been selected for one end of the repeater the same operation is re eated for the other end.

urin'g the process of selection and during the entire time that networks are being selected for the two ends of the repeater,'a master rela associated with the repeater,

is energize Selection cannot take place 'to a minimum.

. unless this relay is energized and the circuits of the several master relays corresponding to each repeater are so arranged that when the master relay of any repeater is energized no other master relay can be actuated until the energized master relay is restored to normal, at the completion of the selection for the corresponding repeater. By,

means of this arrangement but one repeater may select networks at a time, thereby avoiding a possibility of false selection.

At certain times the composite sets, or other auxiliary apparatus associated with certain lines, are disconnected therefrom and it is therefore, desirable that when such apparatus is disconnected from any circuit the selection of a corresponding balancing network be prevented upon the association of a repeater with such circuit. Accordingly, arrangements are provided whereby when the composite sets are disconnected from the side circuits of a group of trans mission lines, comprising the side and phan-.

tom conductors, simplex circuits are prepared for the side circuit and corresponding phantom, said simplex circuits including the talking conductors of the affected transmission lines. With the circuits in this condition, the association of a repeater with either a side circuit or a hantom circuit completes the correspon ing simplex circuit and actuates means to hold open the circuits of the selecting relays of that repeater which, control the selection of "the auxiliary networks for balancing thecomposite sets.

One of the objects of the arrangement above described is to provide a network sclecting arrangement such that false operation of the selecting devices will be reduced Another object is to provide a means whereby selectionby more than one repeater at a time is prevented in a positive manner. Still another object of the invention is the provision of means for preventing the selection of networks for balancing auxiliar equipment when the corresponding auxi iary equipment has been removed from the line, said means being controlled over the talking circuit instead of over the sleeve circuit as. has been the practice heretofore.

'These features, as well as other objects of the invention will be clear from the following description of the invention when read in connection with the accompanying drawings, Figures 1, 2 and 3 of which, when placed end to end, constitute a circult d1agram of a preferred embodiment of the invention.

Referring to the drawings, a cord circuit repeater R, comprising amplifiers A and A terminates in plugs P, and P adapted to be inserted in jacks, such as J J 2 and so forth, of transmission lines, such'as L,, L and so forth. Transmission lines L,, L and L constitute a group of which the lines L, and L are side circuits while the line L 1s the corres onding phantom circuit. Lines L L an L are similarly related. Each of the lines L,, L L, and L is provided with a composite set for telegraphic purposes, the sets of the several lines being s mbolically represented at X,, X,, X, and

respectlvely.

The left hand end of the repeater R is provided with a plurality of networks normally disconnected therefrom, the network LN, being adapted to balance the lines L, or L and the "network PN, being adapted to balance the phantom line L,.

The network XN, is adapted to balance the composite sets X, and X associated with the lines L, and L while another 'network XN, is adaptedto balance the composite sets X, and X with respect to the phantomline L,. Additional networks may be provided for as many other types of lines and auxiliary apparatus as maybe present in the system. In a similar manner, the right hand end of the re ater is provided with networks LN,, P XN and XN, and so forth. Selecting relays for controlling the connection of the proper network or networks to each end of the repeater upon its association with the transmission llne are provided, as will more fully ap ear hereinafter.

' 11 order that the composite-set X, may be removed from the transmission line L, twin jacks J and J,, are provided, these jacks being so arranged that when twin plugs P, and P,, are inserted therein the composite set X, is disconnected from the line and a direct connection is established in its place. Similar arrangements are provided for removing the composite sets X X and X When the composite set is removed from a line it is desirable that means he provided to prevent the repeater from selecting .a network for balancing the composite set. Accordingly, a simplex circuit is associated with the talking conductors of bev closed at one point by the insertion of a each transmission line, which is adaptedto twin plug in the corresponding twin jack for removing the composite set, When the repeater is associated with the line the simplex circuit is completed through a relay which is prepared at the same time that the composite sets are removed from the side circuits.

A master relay MB is provided for the repeater R and similar master relays MR, MR", and so forth, are provided for other repeaters. In order that a repeater, such as B, may select networks, the corresponding master relay-MR must be energized and remain ener 'zed until the networks are selected for 0th ends of the repeater. The circuits of these master relays are so arranged that when the master relay of one repeater is energized no other master relay can be operated until the master relay which is energized is restored to normal at the end of a rocess of selecting networks. Consequent y, but one repeater may select networks at any given instant.

It is believed that the invention is of such a nature that further details of the apparatus may be best understood from a description of the operation thereof, which is as follows: Assuming that it is desired to connectthe side circuit transmission line L, with the phantom transmission line L, through the repeater R, the repeater operator inserts the plug P, in the jack J, of the line L, and the plug P in the jack J, of the line L,. As a result of these operations, sleeve circuits are completed as follows: from battery, through sleeve relay 1, over the sleeve contacts of plug P, and jack J through the windings of sleeve relay 2 and marginal relay 3, associated with the line L,, to ground. Relays 1 and 2 are energized over this circuit but the relay 3 being marginal, does not attract its armature. Relay 2 disconnects battery from the winding of relay 4 which is connected through equal resistances to a simplex circuit extending over the'talking conductors of the line L,. A circuit is also completed from battery through the winding of sleeve relay 5, sleeve contacts of plug P and jack J 5 and through the windings-of sleeve relay 6 and marginal relay 7 associated with the line J Relays 5 and 6 areenergized-but the relay 7, like relay. 3, is marginal and .does not attract its armature. Relay 6 disconnects battery normally connected to the midpoints of the resistances brid ed across the conductors of of master relay MB and thence in series over the extreme right hand back contacts of succeeding master relays MR, MR", and so forth, of other repeaters, to ground. It will be seen that since this circuit passes through the contacts of all the master relays of the other repeaters,-the relay MR cannot be energized if any other master re lay is actuated. Consequently, if at the time the repeater controlling key K was actuated the master relay of another repeater was energized, the circuit above described would not be completed until the master relay of the other repeater is restored to normal, which does not occur until the com letion of the selecting operation for the ot er repeater. Assuming, however, that noother master relay is actuated, the master relay MR is energized over the circuit above traced and upon attracting its right hand armature opens the energizing circuit of all of the other master relays, such as MR and MR, which, it will be noted, pass over the right hand back contact of the relay MB.

The enerigization of master relay MR also completes the following circuit; from battery, over the right hand frontcontact of relay MR, back contact of relay 10, left hand front contact of relay MRthrough th winding of sleeve relay 1 and over the sleeve circuit previously traced through the marginal relay 3 to ground. The current over the sleeve circuit is now sufficiently increased to energize marginal relay 3 which attracts its arniatures', witha result to be presently stated. At the same time that the above circuit was completed an additional circuit was established from battery, over the right hand front contact "of relay am, upper back contact of relay 8, over conductor 11, and thence in parallel through the windings of controlling relays 12, 13, and so forth, to ground. Battery is also connected over the front right hand contact of relay MR and upper back contact of relay 8, through the winding of relay 14 to conductor 15, so that when the controlling relays 12, 13, and so forth, are energized battery is applied over the front contacts of said controlling relays to all of the selecting relays, such as #16, 17, 18, 19, and so forth, associated with. the left end of the repeater. Consequently, when marginal relay 3 attracted its armatures acircuit was completed as follows: from ground, over the lower front contact of relay 3, upper normal contact of selecting relay 16, through the winding and over the lower normal contact of said relay and over. the left hand front contact of relay 13 to battery connected to conductor 15. At the same time an additional circuit was completed from ground, ever the upper 1 front contact of marginal relay 3, over theupper normal contact of selecting relay 18, throughthe winding and over the lower normal contact of said relay and over the left hand front contact of controlling relay 12 to battery connected to conductor 15. Since battery is applied to the circuits above traced over the conductor 15, through the winding of relay 14, said relay 14 is energized and at its lower front contact short circuits the winding of relay 10.

Selecting relays 16 and 18 are energized over the circuits above traced and are locked up independently of marginal relay 3 and controlling relays 12 and 13 over a circuit from battery, right hand front contact of relay MR, lower front contact of relay 14, through resistance 20, conductor 21, and thence in parallel over the lower front contacts of relays 16 and 18, through the windings of said relays and over the upper front contacts of said relays to ground. As soon as all of the selecting relays controlled-by the marginal relay of the line are energized and locked up, (in this case relays 1:6 and 18), the circuits traced through the winding of relay 14 are all opened so that said relay is deenergized and opens a short circuit about the winding of relay 10. The locking circuits just traced for the selecting relays now extend from resistance 20 to battery through the winding of relay 10 and over the front right hand contact of relay 'MR. Relay 10 is accordingly energized and upon attracting its armature opens-the direct battery connection hereinbefore traced, over the left hand front contact of relay ME to the sleev circuit, so that the current flow over the sleeve circuit is reduced sufiiciently to cause the denergization of marginal relay 3 and the consequent opening of the initial energizing circuits of relays 16 and 18. Relay 16 functions to connect the balancing network LN, to the balancing circuit 22 associated with the left end of the repeater R for the purpose of balancing the transmission line L,-. Selecting relay 18 at its upper front contact completes a circuit from loattery through the winding of relay 23, over the back contact of relay 24 and through the winding of relay 25 to ground. Relay 25 disconnects the two sections of balancing circuit 22, while the relay 23 connects the balancing network XN, between the two sections for the purpose of balancing-the composite set X,.

If the composite set X, had been removed from the line L by inserting plugs P and P,, in the jacks J and J a simpler: circuit would have been completed as follows: from ground, over the sleeve contacts of the plugs and jacks just mentioned, through the winding of relay 4:, and thence in parallel through resistances 26 and 2'? over the tip and ring contacts of the jacks d", and plug P through resistances 28 and 29 in parallel and thence through the winding of relay 2% to battery. Relay 24 is energized over the simplex circuit above traced and upon attracting its armature holds open the circuit previously traced through the windings of relays 23 and 25. Consequently, these relays will not be operated and the network XN will not be interpolated in the balancing circuit 22. The energization of relay 4 upon the completion of the simplex circuit connects ground to the midpoint of the simplex resistance connected across the phantom line L so that upon the connection of a repeater with the phantom line the relay of said repeater corresponding to relay 24 will be energized to prevent the selection of the phantom. composite balancing network, as will more clearly appear hereinafter.

Returning to the relay 10, the energization of said relay in addition to causing circuit changes already described, results in the completlon of a circuit from battery, over the front. right hand contact of relay MR, over the front contact of relay 10 and through the winding of relay 8 to ground. Relay 8 upon being energized, by opening its upper back contact breaks the circuit of the controlling relays 12 and 13 and at its lower front contact establishes a new holding circuit for the relay MR, from battery, over the lower front contact of relay 8, front contacts of relays 1 and 5, lower back contact of relay 9, through the winding of relay MR to ground over a circuit previously traced. Over the middle front contact of relay 8 a circuit is completed from battery, front right hand contact of relay MR, middle front contact of relay 8, back contact of relay 30, through the winding of sleeve relay 5, to ground, over a circuit previously traced through the marginal relay 7. Since battery is thus directly applied to the sleeve circuit, the current flow thereover is increased sufiiciently to energize marginal relay 7, with results hereinafter stated;

At the same time" that the circuit above traced for marginal relay 7 was completed an additional circuit was established as follows: from battery, over the right hand front contact of relay upper front contact of relay 8, upper back contact of relay 9 and over conductor 31 and through the windin s of controllin relays 32, 33, and so forth, to ground. B attery is at the same time connected through the winding of relay 34 to conductor 35, so that upon the energizaticn of the various controlling relays, such as 32 and 33, circuits are prepared over the front contacts of said controlling relays for the various selecting relays, such as 36, 37, 38, 39, and so forth. Consequently, the energizati'on of marginal relay 7 results in the completion of a circuit from ground, over the lower front contact of said marginal relay, over the upper back contact of selecting relay 37, through the winding and over the inner lower back contact of said relay, over the left hand front contact of relay 33, over the conductor 35, through the winding of relay 34 and thence over a circuit previously traced to battery. A similar circuit is also completed for selecting relay 39, from ground, over the upper front contact of marginal relay 7, middle back contact of relay 39, through the winding and over the lower back contact of said relay and over the left hand front contact of relay 32, over conductor 35 to battery through the winding of relay 34.

Relay 34 is energized over the circuits above traced and maintains the winding of relay 30 shorted circuited. Relays 39 and 37 upon being energized establish locking circuits from ground, over their front contacts and over conductor 40, through resistance 41, over the lower front contact of relay 34 and thence to battery over a circuit already traced through the upper front contact of relay 8. As soon as all of the selecting circuits whose initial energization circuits were completed have been energized and locked up the relay 34 is deenergized and opens a short circuit about the winding of the relay 30 which is now included in the locking circuit of the selecting relays, through resistance 41 and over conductor 40. Relay 30 upon being energized o ens the direct battery connection tothe s eeve circuit so that the current flow over said circuit is reduced and the marginal relay 7 is deenergized,- thereby opening the initial energizing circuits of the selecting relays 39 and 37. At its front contact relay 30 completes a circuit for relay 9 as follows: from battery, over the right hand front contact of .relay MR, middle front contact of relay 8, front contact of relay 30 and through the winding of relay 9 to ground.

Relay 9 upon being energized opens a battery connection which was traced over its upper back contact to conductors 31 and 35, so that the controlling relays 32, 33, and so forth, are restored to normal. By opening its lower back contact said relay opens a circuit previously traced for the master relay MR, which is restored to normal. Hdlding circuits for relays 8, 10, 9, and 30 are at the same time established over the lower front contact of relay 9 independent of the relay MR as follows: from battery, over the lower front contact of relay 8, front contact of relays l and 5, make contact of repeater controlling key K, lower front contact of relay 9 to point 42, from which one branch extends over the lower front contact of relay 10 and through the winding of relay 8 to ground. Another'branch extends from point 42, through the winding of relay 10 and through the. resistance 20,

armac over conductor 21 and through the locking circuits of the selecting relays 16 and 18 to ground. An additional path extends from point 42 over the upper front contact of relay 8, through the winding of relay 30, through resistance 41, over conductor 40 and over the locking circuits previously traced for relays 39 and 37 to ground. Still another path extends from point 42, over the middle front contact of relay 8, lower front contact of relay 30 and through the winding of relay 9 to ground. Relays 8, 10, 9 and 30 as well as the various selecting relays will, therefore, remain energized so long as the repeater control key K remains actuated and the sleeve relays 1 and 5 are I and 39, which are locked up energized.

Returnin now to the selecting relays 37 over circuits previously traced, it will be noted that the relay 37 functions to connect the network PN to the balancing circuit 43 at the right endlof the repeater in order to balance the phantom line L The selecting relay 39, at its upper front contact completes a circuit from battery, through the winding of relay 44, over the upfier front contact of relay 39, over the lower back contact of relay 45, through the winding of relay 46 to ground. Relay 46 opens the two sections of the balancing circuit 43, while relay 44 connects the phantom composite network XN, between the two sections for the purpose of balancing the effect of the composite sets X and X with respect to the phantom line L,,.

In case the composite sets X and X, has been removed from the side circuits L, and L by inserting plugs P P P and P in jacks J J and J respectlvely, the following circuit would have been completed: from ound, over the sleeve contacts of jack and plug P in parallel with the sleeve contacts of jack 5 and plug through the winding of relay 46 and 15 over the back contact of relay 47 to battery. A circuit would also be completed from ground, over the sleeve contacts of jack and plug P in parallel with the sleeve contacts of jack J and plug P through the windin of relay 48 and over theback contact of relay 49 to battery. The energizetion of relays 46 and 48 over the circuits above traced results in the connection of round over the front contact of said relays to t e midpoints of resistances 50 and 51 bri ged across the talking conductors of the phantom line L Consequently, the insertion of the plug P of the repeater R in the jack 3, of the phantom line L, would result in completing a circuit from batte through the winding of relay 45 to the midpolnts of resistances 52 and 53 and thence in parallel through said resistances over the tip and rin contacts of plug P and jack 3,, 1n paralle balancing circuit 43.

The apparatus will be returned to normal eitherby restoring the key K or by withdrawing the plugs P and P with the consequent deenergization of the sleeve relays 1 and 5. This follows from the fact that battery was supplied over the contacts of relays 1 and 5 and the contact of the key K for locking up relays 8, 10, 9 and 30, as well as the operated selecting relays 16, 18, 37 and 39.

The arrangements above described provide a simple and efiicient circuit arrangement for selecting repeater networks with minimum possibility of false selection and also aiford suitable means for automatically determining whether or not the balancing arrangement for the composite sets shall be included in the balancing circuit. While the invention has been shown as incorporated in a certain circuit arrangement, it will be obvious that the general principles herein disclosed may be embodied in many other organizations widely different from those illustrated without departing from the spirit of the invention as defined 1n the following claims.

What is claimed is:

1. In a signaling system, a plurality of lines of difi'erent types, repeaters for interconnecting said lines, balancing networks for each type of line, a plurality of selecfing relays for each repeater, controlling relays for said selecting relays associated with each repeater, means responsive to the association of a repeater with a line to cause said controlling relays pf that repeater to prepare circuits for all of the selecting relays of that repeater, means determined by the line with which the repeater is associated for completing, a circuit for a selectin relay corre sponding to that type of me only, and means responsive to the actuation of said selectin relay to associate a balancing network with the repeater and to hold open the circuits of said controlling relays.

2. in a signaling system, a plurality of lines of different types, repeaters for interconnecting said lines, balancing networks for each type of line, a plurality ofvselectsponding to that type of line only, means re- SPOIISl B to the actuation of said selecting relay to associate a balancing network with the repeater and to lock up said selecting relay, and means responsive to the locking up of said selectingrelay to open and hold open the circuitsof said controlling relays.

3. In a signaling system, a plurality of lines of different types, repeaters for interconnecting said lines, balancing networks for each type of line for each end of said repeaters, a plurality of selecting relays for each end of each repeater, sets of controlling relays for said selecting relays associated with each end of each repeater, means responsive to the association of the two ends of a repeater with lines to be connected through the repeater to cause the controlling relays associated with one end of the repeater to prepare selecting circuits for all the selecting relays associated with that end of the repeater, means determined by the line with which that end of the repeater is connected for completing a circuit for a selecting relay corresponding to that type of line only, means responsive to the actuation of said selecting relay to associate a balancing network with that end of the repeater, to hold open the circuits of the controlling relays associated with that end of the repeater, and to cause the controlling relays associated with the other end of the repeater to prepare circuits for all of the selecting relays associated with the other end of the repeater means controlled by the line with which the other end of the repeater is associated for completing a circuit for a selecting relay associated with that end of the repeater and corresponding to that type of line only, and means responsive to the actuation of said selecting relay to associate a balancing network with the other end of the repeater and to hold open the circuits of the controlling relays associated with the other end of the repeater.

4. In a signaling system, a plurality of lines of difierent types, repeaters for interconnecting said lines, balancing networks for each type of line for each end of said re peaters, a lurality of selectin relays for each end 0 each repeater, sets 0 controllin relays for said selecting relays associated with each end of each repeater, means responsive to the association of the two ends of a repeater with lines to be connected through the repeater to cause the controlling relays associated with one end of the re: peater to prepare selecting circuits for all the selectingrelays associated with that end of the repeater, means determined by the line with which the end of the repeater is connected for completing a circuit for a selecting relay corresponding to that type of line only, means responsive to the actuation of said selecting relay to associate a balancing network with that end of the repeater and to lock up said selecting relay, means responsive to the locking up of said selecting relay to open and hold open the circuits of the controlling relays associated with that end of the repeater and to cause the controlling relays associated with the. other end of the repeater to prepare circuits for all of the selecting relays associated with the other end of the repeater, means controlled by the line with which the other end of the repeater is associated for completing a circuit for a selecting relay associated with that end.of the repeater and corresponding to that type of line only, means responsive to the actuation of said selecting relay to associate a balancing network with the other end of the repeater and to lock up said selecting relay, and means responsive to the locking up of said selecting relay to open and hold open the circuits of the controlling relay associated with the other end of the repeater.

5. In a signaling system, transmission lines, auxiliary apparatus associated with said transmission lines, a repeater, networks for balancing said transmission lines and said auxiliary apparatus, means whereby when said repeater is associated with a transmission line a network is selected to balance said line, and another network is selected to balance said auxiliary apparatus, and means controllable over the talking conductors of said transmission line to defeat the selections of the latter network.

6. In a signaling system, transmission lines, auxiliary apparatus associated with said transmission lines, a repeater, networks for balancing said transmission lines and said auxiliary apparatus, means whereby when said repeater is associated with a transmission line a network is selected to ballancesaid line, and another network is se lected to balance said auxiliary apparatus and means controllable over a simplex circuit including the talking conductors of said transmission line to defeat the selection of the latter network.

7. In a signaling system, transmission lines, auxiliary apparatus associated with certain of said transmission lines, a repeater, networks for balancing said transmission lines and said auxiliary apparatus, means whereby when said repeater is associated with a transmission line including auxiliary apparatus, networks are selected for balancing said line and auxiliary apparatus, and means controllable over the talking conductors of the transmission line for defeating the selection of a network for balancing the auxiliary apparatus when said repeater is associated with a line having no auxiliary apparatus.

8. In a signaling system, transmission lines, auxiliary apparatus associated with certain of said transmission lines, repeater networks for balancing said transmission lines and said auxiliary apparatus, means whereby when said repeater is associated with a transmission line includingauxiliary apparatus, networks are selected for balancing said line and auxiliary apparatus, and means controllable over a simplex circuit including the talking conductors of the transmission lines for defeating the selection'of a network for balancing the auxiliary apparatus when said repeater is associated with a line having no auxiliary apparatus. v

9. In a signaling system, transmission lines, auxiliary apparatus associated with said transmission lines, a repeater, networks for balancing said transmission lines and said auxiliary apparatus, means whereby when said repeater is associated with a transmission line a network-is selected to balance said line, and another network is selected to balance said auxiliary apparatus and means responsive to the disconnection of the auxiliary apparatus from a trans-' mission line to prepare a simplex circuit over the talking conductors of said line,

whereby the selection of a network to balance the auxiliary apparatus may be defcated when a repeater is associated with cluding the side circuit conductors of the two transmission lines, auxiliary apparatus associated with the conductors of each side circuit, a repeater, a plurality of networks for balancing said side circuits, phantom circuit and auxiliary apparatus, means whereby when the repeater is associated with any one of said lines networks are selected to balance the line and the auxiliary apparatus associated with its conductors, an means responsive to the disconnection of the. auxiliary apparatus from the side circuit conductors to prepare simplex circuits over the talking conductors of the side circuit and the phantom whereby the selection of a balancing network for the auxiliary apparatus will be prevented when the repeater is associated with either the side circuit or the phantom.

In testimony whereof I have signed my name to this specification this thirtieth day of December, 1918.

'- CHARLES S. DEMAREST. 

